1. Field of the Invention
The present invention relates to a delta pixel circuit and a light emitting display, and more particularly, to a delta pixel circuit and a light emitting display having three delta-arranged light emitting diodes connected with one pixel circuit to be emitted to thereby provide a simple wiring structure and a high aperture ratio.
2. Discussion of Related Art
Recently, various panel display devices having weight and volume less than a comparable cathode ray tube have been developed. A light emitting display panel device (or light emitting display) using a light emitting diode (LED) is of special interest because of its fast response time and outstanding emitting efficiency, brightness, and angular field.
An LED emits light when an exciton is generated by a recombination of an electron and a hole and then falls to a low energy level. The LED can be composed of organic electroluminescent layers or inorganic electroluminescent layers and, thus, can be categorized as either an organic light emitting diode (OLED) including organic electroluminescent layers or an inorganic light emitting diode including inorganic electroluminescent layers according to the material and structure of the LED.
Also, an arrangement pattern for LEDs in a light emitting display can be classified as either a delta arrangement pattern or a stripe arrangement pattern.
FIG. 1 shows an exemplary block diagram having a pixel arrangement of a delta pattern in an organic light emitting display according to the prior art.
As shown in FIG. 1, the delta arrangement is repeatedly arranged so that unit pixels 11 having red, green, and blue colors in even rows may deviate in position from corresponding unit pixels 11 in odd rows at regular intervals. In the delta arrangement, a data line (e.g., a data line Dm−1) supplies a data signal representing one color (e.g., green).
FIG. 2 shows a schematic circuit diagram of unit pixels in an organic light emitting display according to the prior art.
As shown in FIG. 2, in a unit pixel, a source of a first transistor T1 is connected with a power supply Vdd, a drain of the first transistor T1 is connected with a source of a third transistor T3 and a gate of the first transistor T1 is connected with a first node A. The first node A is connected with a drain of a second transistor T2. The first transistor T1 supplies a current corresponding to a data signal to an organic light emitting diode OLED.
A source of the second transistor T2 is connected with a data line D1, a drain of the second transistor T2 is connected with the first node A and a gate of the second transistor T2 is connected with a first scanning line S1. As such, the second transistor T2 supplies the data signal to the first transistor T1 according to a scanning signal supplied to the gate of the second transistor T2.
The source of the third transistor T3 is connected with the drain of the first transistor T1, a drain of the third transistor T3 is connected with an anode electrode of the organic light emitting diode OLED, and a gate of the third transistor T3 responds to a light emitting control signal by being connected with a light emitting control line E1. Accordingly, a light emission of the organic light emitting diode OLED is controlled by controlling a current which flows from the first transistor T1 to the organic light emitting diode OLED according to the light emitting control signal.
A capacitor Cst is connected with the first power supply Vdd via a first electrode of the capacitor Cst, and a second electrode of the Cst is connected with the first node A. Because of this, the capacitor Cst can maintain a charge according to the data signal and supplies a signal to the gate of the first transistor T1 according to the maintained charge during one frame to thereby maintain an operation of the first transistor T1 during one frame.
However, because one pixel circuit is connected with only one light emitting diode OLED, a large number of pixel circuits are needed to emit a plurality of light emitting diodes OLEDs.
Also, because one light emitting control line needs to be connected with a pixel row, an aperture ratio of the conventional light emitting display is reduced due to the light emitting control line.